A groundbreaking study conducted by researchers at McGill University indicates that human sleep patterns, or chronotypes, exist on a broader biological spectrum. Each subtype is linked to distinct health and behavioral traits, challenging the conventional ‘early riser vs. night owl’ classification.
Zhou et al. The study identifies five distinct biological subtypes, each related to various behavioral patterns and health conditions. Image credit: Wok & Apix.
Chronotype refers to the specific time during the 24-hour cycle when an individual naturally feels the most alert or is prepared for sleep.
Previous research has often associated late-onset chronotypes with health issues, yet the findings have frequently been inconsistent.
“Instead of asking if night owls face greater risks, it may be more insightful to explore which specific night owls are at risk and why,” explains Dr. Yue Zhou, a researcher at McGill University.
Utilizing AI technology, Zhou and colleagues analyzed brain scans, questionnaires, and medical records from over 27,000 adults in the UK Biobank.
Their findings uncovered three night owl subtypes and two early riser groups.
One early riser subtype exhibited the fewest health issues, while the other was more closely linked to depression.
Night owls performed better on cognitive assessments but faced difficulties in emotional regulation.
One night owl group was prone to risk-taking behaviors and cardiovascular challenges, while another group showed higher tendencies for depression, smoking, and heart disease.
“These subtypes are not merely characterized by their sleep times,” stated Dr. Danilo Buzdok from McGill University.
“They represent a complex interaction of genetic, environmental, and lifestyle factors.”
Instead of categorizing sleep types as good or bad, the researchers emphasize how risks and strengths are distributed differently among the five profiles.
A nuanced comprehension of sleep profiles can clarify why identical sleep schedules impact individuals differently, promoting research and sleep support that transcends a one-size-fits-all methodology.
“In today’s digital age and post-pandemic world, sleep patterns are more diverse than ever,” remarks Zhou.
“Recognizing this biological diversity may ultimately lead to more personalized strategies for sleep, work schedules, and mental health support.”
For further details, refer to the published findings in the Journal on December 22, 2025, Nature Communications.
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L. Joe et al. (2025). Potential brain subtypes of chronotypes reveal unique behavioral and health profiles across population cohorts. Nat Commune 16, 11550; doi: 10.1038/s41467-025-66784-8
Source: www.sci.news
